1. Field of the Invention
The present invention relates in general to a removable seat for attachment to a support and in particular to a boat seat mounting structure including a rotatable seat mounted on a base which slidably holds a plurality of support-engaging members selectively adjustable to accommodate different widths of boat thwarts.
2. Description of the Prior Art
Small boats are provided with thwarts upon which passengers can be seated. Typically, a thwart consists of a flat wooden or metallic plank extending transversely across the boat. Such planks are uncomfortable to sit on for long periods of occupancy in the boat. Furthermore, such thwarts do not have back rests which provide back support for the passengers. Thus, it would be desirable to provide a boat seat mounting structure which could be removably secured to the thwart for providing greater passenger comfort.
A number of boat seat attachments are known in the art. Such attachments generally vary as to the means for releasably securing the seat base to the thwart of the boat. For example, U.S. Pat. No. 2,843,348 to Samuels discloses a detachable mounting for boat seats wherein a plurality of thwart-engaging cams are rotatably mounted on opposing ends of a pair of telescoping inner and outer members. A crank is journalled for rotation in the outer end of the outer member and is in unitary assembly with a rod disposed therein. The rod has a screw-threaded inner end disposed in a complementary screw-threaded recess in the inner end of the inner member. Rotation of the crank rotates the rod and, therefore, causes the cams to move together and grip the boat thwart. Similarly, U.S. Pat. No. 3,591,112 to Garmhausen discloses a boat seat clamp having a horizontal bar which can be adjusted lengthwise. A clamp member is slidably mounted on one end of the bar and locked to the bar by cam action under clamping pressure applied by an operator so as to frictionally engage the thwarts.
U.S. Pat. No. 3,718,365 to Gibson discloses a seat attachment for boats which includes a rectangular, tubular main frame having clamp means for detachably securing the frame to the sides of the boat. A sub-frame carrying a seat is engaged with opposite sides of the tubular main frame to permit sliding adjustment of the sub-frame longitudinally of the main frame. U.S. Pat. No. 3,789,444 to McCord discloses a boat seat holder assembly including a pair of bracket plates interconnected by a swivel plate seat mounting assembly. The forward plate has a substantially monoplanar main plate portion with a turned-over flange at the forward edge thereof. The rear bracket plate has a substantially monoplanar main portion with a first flange portion bent from and extending at a right angle to the main plate portion. The front and rear bracket plates cooperate to frictionally engage the permanent seat of a boat.
U.S. Pat. No. 3,821,825 to Bailey discloses a removable boat seat attachment having a seat rotatably mounted on a base member. The base member has seat board engaging members which cooperate with an adjustable clamp having seat board engaging portions such that the engaging member and the clamp engage opposite edges of the seat board for securing the base member thereto. Quick release locking-type fasteners have portions secured to the base member and the clamp for urging and normally maintaining the seat board engaging portions in clamping engagement and removably securing the boat seat attachment thereto.
The boat seat constructions of the prior art suffer from several deficiencies. Many of such constructions are not adaptable to thwart structures of different sizes. Others require time-consuming effort to attach the seat to the thwart and release it therefrom. Those constructions which avoid these problems suffer from expensive and complicated mounting structures.